Of course there's no official DSM-IV code and every person with a tattoo is different, but I in general would say a mix of being impulsive, lack of respect for your own body/being estranged from nature and sensitive to getting attention.
DSM-IV-TR is no longer in use. It's the DSM-V.
If you're going to say that X population had a mental illness, at least try to keep up with the literature.

How is it impulsive when people sometimes wait 10 years to get a tattoo? I wouldn't consider that impulsive.
If getting tattoos is disrespectful toward ones body, then so is doing steroids or drinking. Although we would have to determine what you mean by "lack of respect."
I believe people who compete in bodybuilding like yourself do it for attention. I guess you're not that much different than those who get tattoos.